A door closer is disclosed in previous European patent application number EP-A-59503 in which during a final part of the closure movement of the door, increased thrust is applied to the door to overcome the force of, for example, a sprung door latch. In that proposal a thrust mechanism including an arrangement of balls and detents is described.
An improved mechanism for achieving the application of increased thrust during the final part of the closure movement of the door is described in later International patent application number WO-A-02/063125. In this proposal, a cam mechanism including a slot and cam follower is provided to apply the increased thrust. The present invention represents an improvement over two former proposals.